Can onLayout also provide the page position, like measure does?

Description

The onLayout callback now provides in its layout data the same information as the measure (NativeMethodsMixin) callback does, except for the missing absolute page position. Is there a technical reason for this, or can these 2 values also be included in the onLayout data?

I’m now calling measure (i.e. triggering the callback) in the onLayout callback, in order to know when measure() can provide (update) information, but this seems to be double work.

[scally]

So, there’s a workaround for this, but it’s really awkward – you need to save a child view as a ref, and then use that ref in a callback in another callback in onLayout.

There are legitimate use cases for absolute page positioning, one of which is drag/drop; if you want to know if one component has been dropped onto another when the two don’t share a common immediate parent.

If there’s no technical limitation preventing this from being surfaced as a param to onLayout (or on another event handler) then could we re-open this issue?

[scally]

the workaround looks like this, fwiw:

render() {
    return (
      <View
        ref={ref => this.view = ref}
        onLayout={() => this.saveLayout()}
        >
  )
}

// later....

saveLayout() {
  this.view.measureInWindow((x, y, width, height) => {
    // do a thing with the layout...
  }
}